Method for operating a wind turbine

ABSTRACT

The present invention relates to a method for operating a wind turbine with the steps: detection of the values of predetermined operating parameters by means of suitable sensors, detection of at least one predetermined initial condition, comparison of the detected values to stored values of the operating parameters. The invention further relates to a wind turbine for implementing the method._Therefore, the object of the present invention is, to be able to adapt the operation of a wind turbine to changes using a method of the type named above, such that when the detected parameter values deviate from the stored parameter values, as a function of the initial condition, either the stored parameter values are adapted to the detected parameter values or the operation of the wind turbine is influenced as a function of the detected parameter values._In this way, the invention is based on the knowledge that, from a pragmatic view, the formation of ice on a rotor blade is also a (temporary, meteorologically-related) change to the rotor blade shape. From this it follows that the formation of ice on the rotor blades always leads to a change of the aerodynamic profile and thus to a negative effect of the output of the wind turbine. However, deviations from this shape and thus deviations in the magnitude of the generated output also result just from manufacturing-dependent deviations of the rotor blades from the predetermined optimum shape and from gradual soiling of the rotor blades during operation.

The present invention relates to a method for operating a wind turbinewith the steps: detecting the values of predetermined operatingparameters by means of suitable sensors, detecting at least onepredetermined initial condition, and comparing the detected values tostored values of operating parameters. The invention further relates toa wind turbine for realizing the method.

Here, the term “parameter” or “operating parameter” is used in the senseof a directly detected parameter, but also in the sense of a parametervalue derived from a detected value.

Wind turbines have already been manufactured for some time in suchquantities that it is quite acceptable to talk about series production.In the end, however, each wind turbine is definitely unique, becausedeviations from optimum settings also occur in series production. As isknown, this is definitely not a phenomenon of series production of justwind turbines. Instead, in many areas of daily life there are defaultvalues and an acceptable tolerance range, within which deviations fromthe predetermined values are acceptable and not problematic.

Because the rotor blades of wind turbines are produced with anextraordinarily high percentage of manual labor and reach considerabledimensions, each individual rotor blade is unique. Thus, a wind turbinewith three rotor blades already has three unique blades on its rotor.Therefore, a rotor of one wind turbine is not like any other and eventhe exchange of one rotor blade changes the entire rotor, within thetolerance range.

Accordingly, the operating behavior of each wind turbine also differsfrom that of all other wind turbines; even when these are of the sametype. Even if the deviations lie within the permissible tolerance range,they can nevertheless still lead to power losses.

Wind turbines and especially their parts mounted outside in the area ofthe gondola, such as the rotor, but also the anemometer, are subject tothe risk of icing, especially in winter. Icing of the anemometer caneasily lead to measurement errors, which in turn result in unsuitablecontrol of the wind turbine.

Icing of the rotor involves the risk that persons and things in the areaof the wind turbine could be injured or damaged due to falling ice. Whenrotor blades are covered with ice, it cannot be predicted when or howmuch ice will fall, and the wind turbine must be stopped, in particular,due to icing of the rotor blades, in order to prevent endangering thearea.

In the state of the art, various approaches have become known to preventthis problem. Thus, e.g., heated anemometers are available. The heatersof these anemometers should prevent

TECHNICAL FIELD

The present invention relates to a method for operating a wind turbinewith the steps: detecting the values of predetermined operatingparameters by means of suitable sensors, detecting at least onepredetermined initial condition, and comparing the detected values tostored values of operating parameters. The invention further relates toa wind turbine for realizing the method.

Here, the term “parameter” or “operating parameter” is used in the senseof a directly detected parameter, but also in the sense of a parametervalue derived from a detected value.

BACKGROUND INFORMATION

Wind turbines have already been manufactured for some time in suchquantities that it is quite acceptable to talk about series production.In the end, however, each wind turbine is definitely unique, becausedeviations from optimum settings also occur in series production. As isknown, this is definitely not a phenomenon of series production of justwind turbines. Instead, in many areas of daily life there are defaultvalues and an acceptable tolerance range, within which deviations fromthe predetermined values are acceptable and not problematic.

Because the rotor blades of wind turbines are produced with anextraordinarily high percentage of manual labor and reach considerabledimensions, each individual rotor blade is unique. Thus, a wind turbinewith three rotor blades already has three unique blades on its rotor.Therefore, a rotor of one wind turbine is not like any other and eventhe exchange of one rotor blade changes the entire rotor, within thetolerance range.

Accordingly, the operating behavior of each wind turbine also differsfrom that of all other wind turbines; even when these are of the sametype. Even if the deviations lie within the permissible tolerance range,they can nevertheless still lead to power losses.

Wind turbines and especially their parts mounted outside in the area ofthe gondola, such as the rotor, but also the anemometer, are subject tothe risk of icing, especially in winter. Icing of the anemometer caneasily lead to measurement errors, which in turn result in unsuitablecontrol of the wind turbine.

Icing of the rotor involves the risk that persons and things in the areaof the wind turbine could be injured or damaged due to falling ice. Whenrotor blades are covered with ice, it cannot be predicted when or howmuch ice will fall, and the wind turbine must be stopped, in particular,due to icing of the rotor blades, in order to prevent endangering thearea.

In the state of the art, various approaches have become known to preventthis problem. Thus, e.g., heated anemometers are available. The heatersof these anemometers should prevent icing. However, such a heater is notcomplete protection against icing of the anemometer, because, on onehand, the heater could fail and, on the other hand, even a functionalheater cannot prevent the formation of ice to arbitrarily lowtemperatures.

Various designs have also become known for the rotor blades. Forexample, rotor blades can be heated in order to prevent any formation ofice. However, for large wind turbines with correspondingly large rotorblades, the power consumption needed is considerable. From DE 195 28 862A1, a system is known in which the turbine is stopped after there isicing and then the rotor blades are heated in order to eliminate theicing of the rotor blades, with power use optimized as much as possible.However, the detection of icing in the state of the art is frequentlyrealized through the detection of an unbalanced rotor, which resultswhen the rotor drops a part of the already-formed ice.

However, the first time ice falls already represents a danger to thearea; with increasing size of the rotor blades their mass alsoincreases, so the fall of relatively small amounts of ice does not leadto a detectable imbalance, and reliable detection of ice formation isdifficult.

BRIEF SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to be able to adaptthe operation of a wind turbine to changes. This object is achieved forthe method of the type named above such that when the detected parametervalues deviate from the stored parameter values as a function of theinitial conditions, either the stored parameter values are adapted tothe detected parameter values or the operation of the wind turbine isinfluenced as a function of the detected parameter values.

The invention is based on the knowledge that, from a pragmatic view, theformation of ice on a rotor blade also represents a (temporary,meteorologically-related) change of the rotor blade shape, with theresult that the formation of ice on the rotor blades of a wind turbinealways leads to a change of the aerodynamic profile and thus to anegative effect on the output of the wind turbine. However,manufacturing-dependent deviations of the rotor blades from thepredetermined optimum shape and gradual soiling of the rotor bladesduring operation also lead to deviations from this shape and thusdeviations in terms of the generated output.

Now, if predetermined operating parameters, such as wind speed, angle ofattack of the rotor blades, and generated output are detected, these canbe compared to values stored in the wind turbine. Under consideration ofthe initial condition of the outside temperature, from which it can bederived whether icing can occur at all, now either the values stored inthe wind turbine can be adapted to the actual situation or the operationof the turbine is influenced accordingly.

The initial condition of the outside temperature can be monitored with atemperature sensor. If the outside temperature is 2° C. or higher, thenicing can be reliably ruled out and deviation of the values isconsequently reliably not traced back to icing, but instead todeviations as a result of tolerances, e.g., in the rotor blade profile.If the temperature falls below 2° C., icing can no longer be reliablyruled out. Consequently, if the parameter values change, icing cannot beruled out and therefore the operation of the turbine is influenced,e.g., the turbine is stopped.

In order to be able to adapt the parameter values stored in the turbineto continuous changes to the turbine and not to lead to an erroneousdetection of ice formation, the parameter values stored in the turbinecan be adapted accordingly for (repeated) appearance of deviations. Inorder to adapt these parameter values, a difference between the storedparameter value and the detected parameter value is determined and,according to this difference, the values of the stored parameter can bechanged with a predetermined weight. This weight can be, e.g., afraction of the amount of the difference, so that a one-time change doesnot lead to a significant change to the stored parameter values.

The values of the parameters and/or the initial condition can bedetected during a time period that can be preset, e.g., 60 s, and/orduring a preset number of measurement cycles, in order to reduce theinfluence of random single events.

Because the wind turbine is controlled with different parameters as afunction of the wind speed, the parameters used preferably vary as afunction of a second initial condition. Below the wind speed at whichthe turbine generates nominal output, the turbine is controlled by thegenerated output and is dependent on, among other things, the windspeed. Accordingly, the wind speed can be determined from the generatedoutput. When the nominal wind speed is reached and exceeded, the turbinealways generates the nominal output. In this range, the turbine iscontrolled by changing the angle of attack of the rotor blades.Accordingly, a wind speed can be allocated to the angle of attack of therotor blades. Consequently, as a function of reaching the nominal outputas an initial condition, the parameter can change between the generatedoutput and rotor blade angle of attack.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

An embodiment of the invention is explained in more detail below withreference to the figures. Shown are:

FIG. 1, a flow chart of the method according to the invention;

FIG. 2, a flow chart of an alternative embodiment of the method;

FIG. 3, an example of a predetermined standard characteristic line andcharacteristic lines determined by measurements; and

FIG. 4, a representation for illustrating the change of the storedparameter values.

DETAILED DESCRIPTION

Embodiments of techniques for operating a wind turbine are describedherein. In the following description, numerous specific details aregiven to provide a thorough understanding of embodiments. One skilled inthe relevant art will recognize, however, that the invention can bepracticed without one or more of the specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring aspects of the invention.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments.

The individual steps are designated with reference symbols in the flowchart shown in FIG. 1. Step 10 is the beginning of the flow chart. InStep 11, it is tested whether this is the first startup of this windturbine. The branch extending downwards symbolizes the answer “yes” andthe branch extending to the right symbolizes the answer “no.” If this isthe first startup of the turbine, then in Step 12, typical standardvalues are recorded in a memory. If this is not the first startup, thisStep 12 is skipped.

In Step 13, the generated output P_(actual), the rotor blade angle ofattack a, and the wind speed v_(w) are detected. In Step 14, it istested whether the generated output P_(actual) is the nominal outputP_(N). If this is the case, the process continues via the bottom branchto Step 15. There, the rotor blade angle of attack a is selected as theparameter. If the generated output is not the nominal output, i.e., ifit is less than the nominal output, the right branch is used and theprocess continues with Step 16, where the generated output P_(actual) isselected as the parameter. In the subsequent Step 19, it is testedwhether the outside temperature u is at least 2° C. If this is the case,the process continues via the bottom branch to Step 20.

The detection of the outside temperature u can be realized by means of athermometer. Naturally, there can also be another thermometer,optionally at a different location, wherein the temperatures detected bythese thermometers can be checked with one another for plausibility.

In Step 20, depending on the parameter determined in Steps 14, 15, and16, blade angle of attack a or generated output P_(actual), theassociated wind speed V_(K) is determined from the data stored in thewind turbine. Then this wind speed V_(K) is compared to the detectedwind speed v_(w). In Step 21, it is tested whether the detected windspeed deviates from the stored wind speed. If this is the case, theprocess continues via the bottom branch, and in Step 22, a new value isdefined for the stored parameter value and stored in the wind turbine.

This new value is multiplied by a factor of 0.05 as a weighting factorand added to the previous value, taking its sign into account. If asmaller value is produced, then 1/20 of the difference from thepreviously stored value is subtracted; if a higher value is produced,1/20 of the difference is added to this value. After this newlydetermined value has been stored, the generated output P_(actual), therotor blade angle of attack a and the wind speed v_(w) are detectedagain and the process is executed again beginning at Step 13.

Naturally, the weighting factor can also assume any other suitablevalue. Here, it is easy to see that for a larger weighting factor, thestored values are adapted to the detected values more quickly than for asmaller weighting factor.

The weighting factor can also be changed, e.g., as a function of themagnitude of the difference between the detected value and the storedvalue. The greater the difference, the smaller the weighting factor canbe, in order to reduce the influence, e.g., due to a large difference,or vice versa.

Alternatively, a weighting factor can be eliminated. Instead, the storedvalues can be adapted to the detected values independently or in stepsdependent on the differences with predetermined amounts. Thus, theadaptation can always be realized with a value w, or for a predeterminedfirst range of the difference amount, a first predetermined value w₁ isused, and for a predetermined second range of the difference amount, apredetermined second value w₂ is used, and for a third range, a valueW₃, etc.

If the value determined in Step 20 does not deviate at all or notsignificantly from the stored value, the process continues from Step 21via the right branch and Step 22 is bypassed. Accordingly, this Step 22can be spared and thus the load on the processor that is used isreduced.

In Step 19, if it is determined that the temperature is not at least 2°C., icing of the rotor blades can no longer be reliably ruled out.Accordingly, the process branches via the side branch to Step 23. InStep 23, in turn, according to the detected parameters, the wind speedv_(w) allocated to the stored parameter value is determined.

In Step 24, it is tested whether (under consideration of a tolerancerange) the wind speed V_(K) determined from the stored parameter valuesagrees with the detected wind speed v_(w). If this is the case, theprocess returns via the side branch to Step 13 and the processcontinues, in turn, with the detection of the generated outputP_(actual), the rotor blade angle of attack a, and the wind speed v_(w).

In Step 24, when it is recognized that the detected wind speed v_(w)does not agree with the wind speed V_(K) determined from the storedvalues, in Step 25 it is tested whether the detected wind speed v_(w) issmaller than the wind speed V_(K) determined from the parameter values.

If this is the case, the process continues via the bottom branch and, inStep 26, anemometer icing is assumed, because it results from the outputgenerated by the turbine or from the blade angle of attack that the windspeed must be higher than that detected by the anemometer.

If the detected wind speed v_(w) is not smaller than the wind speedV_(K) determined from the stored parameter values, the process continuesvia the side branch and Step 25.

Because it is known from Step 24 that the detected wind speed v_(w) isnot equal to the wind speed determined from the stored parameter valuesV_(K), and because the detected wind speed v_(w) is also not smallerthan the wind speed V_(K) determined from the stored parameter values,it must therefore be greater. However, for this greater wind speed, if asmaller output is generated or a smaller rotor blade angle of attack isdetected, it necessarily follows that the aerodynamic behavior of therotor blades is changed. Because it is known from Step 19 that thetemperature lies below 2° C., icing of the rotor blades cannot be ruledout.

Accordingly, in Step 27 icing of the rotor blades is now assumed.

Both icing of the anemometer assumed in Step 26 and also icing of therotor blades assumed in Step 27 lead to stoppage of the turbine in Step28. Thus, risk to the surroundings is reliably ruled out in each case.

The entire process then ends in Step 29.

In the flow chart shown in FIG. 2, the individual steps are designatedwith reference symbols. Step 10 is the beginning of the flow chart. InStep 11, it is tested whether it is the first startup of this windturbine. The branch extending downwards symbolizes the answer “yes” andthe branch extending to the right symbolizes the answer “no.” If it isthe first startup, then typical turbine standard values are recorded ina memory in Step 12. If it is not the first startup, Step 12 is skipped.

In Step 13, the generated output P_(actual), the rotor blade angle ofattack a, and the wind speed v_(w) are detected. In Step 14, it istested whether the generated output P_(actual) is the nominal outputP_(N). If this is the case, the process continues via the bottom branchto Step 15. There, the rotor blade angle of attack a is selected as theparameter. If the generated output is not the nominal output, it isconsequently smaller than the nominal output, the right branch is usedand the process continues with Step 16, where the generated outputP_(actual) is selected as the parameter.

Accordingly, in Step 17, the stored wind speed V_(K) allocated to theparameter selected in Step 15 or Step 16 is determined. A tolerancerange with a width that can be preset is allocated to this wind speedV_(K). This width can vary, e.g., as a function of the installation siteof the wind turbine.

At installation sites with higher risk to the surroundings, e.g., in thevicinity of buildings, a quick reaction by the controller of the windturbine to deviations of the stored values can be realized through atight tolerance range.

For this tight tolerance range, empirical values of ±0.5 m/s to ±2 m/s,preferably ±1.2 m/s have been determined. For areas with lower risks, arange of ±1 m/s to ±3 m/s, preferably +2 m/s is given as useful.

In Step 18, it is tested whether the detected wind speed v_(w), underconsideration of the tolerance range, agrees with the wind speed V_(K)determined from the stored values. If this is the case, the processcontinues via the right branch from Step 18 and returns to Step 13.There, the wind speed v_(w), the rotor blade angle of attack a, and thegenerated output P_(actual) are detected again.

If the detected wind speed v_(w) does not agree with the stored windspeed V_(K) (naturally, in turn, under consideration of the tolerancerange), the process continues in Step 18 through the bottom branch toStep 19.

In Step 19, it is tested whether the outside temperature u equals atleast 2° C. If this is the case, the process continues via the bottombranch to Step 20.

In Step 20, the associated wind speed V_(K) is determined from the datastored in the wind turbine and also the difference values as a functionof the parameters blade angle of attack a or generated output P_(actual)determined in Steps 14, 15, and 16. In Step 22, a new value is definedfor the stored parameter value and stored in the wind turbine.

This new value is multiplied by a factor of 0.05 as a weighting factorand added to the previous value, taking its sign into account. If asmaller value is produced, then 1/20 of the difference of the previouslystored value is subtracted; if a higher value is produced, then 1/20 ofthe difference is added to this value. After this newly-determined valueis stored, the generated output P_(actual), the rotor blade angle ofattack α, and the wind speed v_(w) are detected again and the process isexecuted again starting at Step 13.

Naturally, the remarks made in the description about FIG. 1 also applyhere for the weighting factor.

In Step 19, if it is determined that the temperature is not at least 2°C., then icing of the rotor blades can no longer be reliably ruled out.Accordingly, the process continues via the side branch to Step 25.

In Step 25, it is tested whether the detected wind speed v_(w) issmaller than the wind speed V_(K) determined from the parameter values.

If this is the case, the process continues via the bottom branch, and inStep 26, anemometer icing is assumed, because it results from the outputP_(actual) generated by the turbine or from the blade angle of attack athat the wind speed must be higher than that detected by the anemometer.

If the detected wind speed v_(w) is not smaller than the wind speedV_(K) determined from the stored parameter values, the process continuesvia the side branch and in Step 25.

Because it is known from Step 24 that the detected wind speed v_(w) isnot equal to the wind speed V_(K) determined from the stored parametervalues, and because the detected wind speed v_(w) also is not smallerthan the wind speed V_(K) determined from the stored parameter values,this must therefore be larger. However, if a smaller output is generatedor a smaller rotor blade angle of attack is detected for this largerwind speed, it necessarily follows that the aerodynamic behavior of therotor blades has changed. Because it is known from Step 19 that thetemperature lies below 2° C., icing of the rotor blades cannot be ruledout. Accordingly, in Step 27, icing of the rotor blades is assumed.

Both icing of the anemometer assumed in Step 26 and icing of the rotorblades assumed in Step 27 lead in Step 28 to stoppage of the turbine.Thus, risk to the surroundings is reliably ruled out in each case.

The entire process then ends in Step 29.

FIG. 3 shows a representation with three characteristic lines. The windspeed v_(w) is given on the abscissa-of the coordinate system. Here, thewind speed v_(w) is the parameter relevant up to the nominal wind speedV_(N), at which the wind turbine reaches its nominal output; above thiswind speed V_(N), the rotor blade angle of attack α is the relevantparameter. However, for reasons of clarity, this is not shown in thefigure.

The output P is recorded on the ordinate. The nominal output P_(N) isindicated.

Let the continuous line be the example for the standard parameter valuesstored in the wind turbine at the first startup. The dashed linedesignates a first characteristic line specific to the turbine formed byadapting the stored standard values to the detected values, and thedash-dot line represents a second example of a characteristic linespecific to the turbine, also formed by adapting the stored standardvalues to the detected values. Naturally, only one characteristic linespecific to the turbine can apply to one wind turbine.

The first dashed characteristic line running below the continuouscharacteristic line already gives a hint that the output actuallygenerated by the turbine lies below the output seen in the standardparameters. In contrast, the second, dash-dot characteristic linerepresents higher outputs in the range up to the nominal wind speedV_(N).

Below the nominal wind speed V_(N), the parameter P_(actual) is used.From the dashed characteristic line it follows that the output P₁ isgenerated at a detected wind speed v₂. From the (continuous) standardcharacteristic line, a wind speed v₁, is given for the output P₁, whichlies below the detected wind speed v₂. The wind speed v₂ detected at theoutput P₁ is thus greater than the wind speed v₁ determined from thestored values. At a temperature below 2° C., according to the invention,the wind turbine would be turned off under the assumption of rotor bladeicing.

At a temperature of at least 2° C., the difference Δv=v₂−v₁ would beformed. As a correction value, Δv/20 is added to the stored value andrecorded in the memory instead of the previous value. Because thedifference Δv has a positive sign, the stored value is shifted in thedirection of larger values, thus in the direction v₂ with 1/20 of theamount of the difference.

The dash-dot line shows a deviation in the opposite direction. At theoutput P₁, a wind speed V₃ is detected which is smaller than the windspeed v₁ determined from the standard characteristic line. Thedifference V₃−V₁ produces, in turn, Δv, and Δv/20 is added as thecorrection value to the stored value. However, in this case, because thedifference Δv is negative, a value with a negative sign is accordinglyadded to the stored value, consequently Δv/20 is subtracted. Thus, herethe stored value is also adapted with 1/20 of the difference, takinginto account the sign, thus in the direction towards V₃.

If the nominal output is reached, thus the nominal wind speed V_(N) isreached or exceeded, then the generated output P_(actual) is no longerdetected as the parameter, but instead, the angle of attack α of therotor blades is detected as the parameter. The further processcorresponds to that explained above. From the detected rotor blade angleof attack α, the allocated wind speed is determined by means of thestandard characteristic line (continuous characteristic line). This iscompared to the detected wind speed. Here, if differences are produced,these processes are as described above.

FIG. 4 is an enlarged representation of a section of the characteristiclines shown in FIG. 3 in a range below the nominal wind speed V_(N). Inthis FIG. 4, the wind speeds are recorded as in FIG. 3.

Through the enlarged representation, the difference can be seen moreeasily. The reference wind speed is the wind speed v₁ determined fromthe stored values. This is subtracted from the detected wind speed V₂,V₃. Accordingly, Δv is produced. For the difference v₂−v₁, Δv has apositive sign. For the difference V₃−v₁, however, Δv has a negativesign.

To prevent too great an influence of these deviations on the storedvalues, the difference is weighted with a preset factor. In the presentcase, let this factor be 0.05.

To adapt the stored values to the individual wind turbine, the weighteddifference, here, Δv/20, is added to the stored value v₁ or icing isassumed for the appearance of a difference at an outside temperaturebelow 2° C. and the operation of the wind turbine is stopped.

In order not to have to react to every arbitrarily small deviation Δv, atolerance range can be provided. This is designated in the figure with−T for the lower limit and +T for the upper limit. For deviations Δv inthe tolerance range, the turbine continues to operate or the valuesstored in the wind turbine are not changed. Obviously, the tolerancerange can apply, e.g., only for the operational control of the windturbine. Then, the stored values are adapted even for small changes, butthe turbine still continues to operate even at temperatures below 2° C.

According to the installation site of the individual wind turbine, thevalues for the tolerance range can be set individually. Where atolerance of ±2 m/s is sufficient for one installation site, a tolerancerange of ±1.2 m/s is necessary for a different installation site of thesame turbine type.

At a wind speed v₁, of 10 m/s, an upper limit of 11.2 m/s and a lowerlimit of 8.8 m/s are given for ±1.2 m/s as the tolerance. Within thisrange from 8.8 m/s to 11.2 m/s, the parameters can be adapted, forexample, but the turbine continues to operate at low outsidetemperatures.

In the figure, let v₁, equal 10 M/s, v₂ equal 12 m/s, and V₃ lie at 8.5m/s. Thus, Δv=v₂−v₁=2 m/s. The adaptation of the stored value isrealized with 1/20, thus, in this example, 0.1 m/s. Because the sign ispositive, v₁ changes accordingly to 10.1 m/s.

For a difference Av=V₃−V₁ a value of 8.5 m/s−10 m/s=−1.5 m/s isproduced. The adaptation of v₁, is realized, in turn, with Δv/20, thus−0.075 m/s. Therefore, v₁, is changed to 9.925 m/s.

The weighting factor determines how fast the stored values are adaptedto the detected values. The greater this factor, the faster theadaptation.

However, the detection of the values also has an affect. Typically, inthe area of the wind turbines, especially environmental values, such astemperature or wind speed, are not determined from a single measurement,but instead from a plurality of measurement cycles, e.g., 30, ordetected over a predetermined time period, e.g., 60 s. The values arethen derived from these results, e.g., as arithmetic or geometric means.

All of the above U.S. patents, U.S. patent application publications,U.S. patent applications, foreign patents, foreign patent applicationsand non-patent publications referred to in this specification and/orlisted in the Application Data Sheet, are incorporated herein byreference, in their entirety.

The above description of illustrated embodiments, including what isdescribed in the Abstract, is not intended to be exhaustive or to limitthe invention to the precise forms disclosed. While specific embodimentsand examples are described herein for illustrative purposes, variousequivalent modifications are possible within the scope of the inventionand can be made without deviating from the spirit and scope of theinvention.

These and other modifications can be made to the invention in light ofthe above detailed description. The terms used in the following claimsshould not be construed to limit the invention to the specificembodiments disclosed in the specification and the claims. Rather, thescope of the invention is to be determined entirely by the followingclaims, which are to be construed in accordance with establisheddoctrines of claim interpretation.

1. A method for operating a wind turbine, the method comprising:detecting values of preset operating parameters using sensors; detectingat least one preset initial condition; comparing the detected values tostored values of the operating parameters; and detecting an outsidetemperature in a region of the wind turbine, wherein if the detectedparameter values deviate from the stored parameter values, as a functionof the at least one initial condition, either the stored parametervalues are adapted to the detected parameter values or operation of thewind turbine is influenced as a function of the detected parametervalues.
 2. The method according to claim 1, wherein the stored parametervalues are adapted when a limit value of the initial condition isexceeded, and wherein when at least one of the values falls below thelimit value, the operation of the wind turbine is influenced.
 3. Themethod according to claim
 1. wherein adaptation of the stored parametervalues is realized with a predetermined weighting of an amount of adeviation from the stored parameter value.
 4. The method according toclaim 1 wherein the detected parameter values and/or initial conditionsare detected during a period that can be preset.
 5. The method accordingto claim 1 wherein the parameter values and/or initial conditions aredetected during a predetermined number of measurement cycles.
 6. Themethod according to claim 1 wherein parameters used vary as a functionof a second initial condition.
 7. The method according to claim 6wherein when a limit value of the second initial condition is exceeded,values of first parameters are used, and when the value falls below thelimit value of the second initial condition, values of second parametersare used.
 8. A wind turbine comprising a device with sensors fordetecting values of preset operating parameters and at least one initialcondition, namely a temperature in a region of the wind turbine, and forcomparison of the detected parameter values to stored values of theoperating parameters, wherein when the detected parameter values deviatefrom the stored parameter values, as a function of the initialcondition, either the stored parameter values are adapted or theoperation of the wind turbine is influenced as a function of thedetected parameter values.
 9. The wind turbine according to claim 8wherein the device includes a microprocessor.